SUMMARY A critical gap exists in the evidence reading the safety and effectiveness of treatments for older adults with chronic low back pain (cLBP). Acupuncture has been found to be effective in treating cLBP in younger adults. Yet trials have rarely included older adults, who have more comorbidities and may respond differently than typical trial participants. We have designed a pragmatic randomized trial to address this gap. After a planning year to refine strategies to identify and recruit patients, finalize acupuncture protocols, and ensure data infrastructure and quality, we will conduct a three-arm trial of 828 adults ?65 years of age with cLBP to evaluate acupuncture versus usual care. We will compare a standard 12-week course of acupuncture with an enhanced course of acupuncture (12-week standard course, plus 12-week maintenance course) to usual medical care for cLBP. The primary outcomes of this large trial will be back- related function at 26 weeks. These and other biopsychosocial measures will be collected at 12, 26, and 52-weeks post randomization. We predict that back-related function in older adults with cLBP will be most improved among participants in the enhanced acupuncture arm, followed by the standard acupuncture arm, and least improved among those receiving only usual care. Medicare is also interested in data on the value of acupuncture for older adults to inform coverage decisions and efficient implementation. As such, to supplement knowledge gained from the effectiveness trial, we will conduct a cost-effectiveness analysis of both forms of acupuncture compared to usual care as well as comprehensive qualitative evaluations to understand, describe and explain barriers and facilitators to adoption, implementation, and sustainability of acupuncture treatment for older adults. Our large sample will be recruited from 4 diverse health plans to represent the ethnic and racial composition of Medicare enrollees as well as the most common ways acupuncture is incorporated in insurance-based care for chronic pain. If successful, this pragmatic RCT will offer clear guidance about the value of acupuncture for improving functional status and reducing pain intensity and pain interference for older adults with cLBP. This evidence will provide essential information for Medicare regarding coverage decisions and for individual physicians and patients deciding on a course of treatment.